Zoonotic spillover is the transmission of a pathogen from animals to humans, usually through some intermediate host.
One such virus is Hendra, a bat-borne virus that primarily infects large fruit bats.
Hendra virus does not kill bats, but it can be transmitted to horses, which are intermediate hosts, and then to humans, causing serious and even fatal diseases.
A recent study published in Nature suggests that changes in climate and land use may have facilitated the spillover of pathogens from bats to other animals.
Researchers analyzed data on land use change, bat behavior, and Hendra virus spillover from bats to horses in subtropical Australia over a 25-year period (1996-2020).
These data show that changes in land use and climate have driven bats’ habitat towards agricultural and urban areas.
Climatic factors such as El Niño lead to a shortage of food for bats, and subsequently bat habitats move closer to areas of human settlement (which can provide a food source).
Similarly, the loss of natural bat habitat has caused bats to roost closer to humans.
Both of these factors are associated with an increased risk of Hendra virus spillover to horses.
The authors note that the above results shed light on the key processes from land use change to behavioral changes in bats in response to changes in food access that lead to virus spillover.